Pachymetra root rot surveys of the Tully district: update 2018

Pachymetra root rot is a soil-borne disease that impacts all sectors of the Australian sugar industry. The disease attacks the root system of sugarcane crops, affecting yields and leading to stool loss and shortened crop cycles, thus impacting the farming, harvesting and milling sectors. Monitoring the disease is, therefore, important so that optimised management practices are adopted, so bringing benefits to the entire value chain. A survey of the Tully district conducted in 2004 showed that pachymetra root rot was widely distributed across the Tully mill area; a second survey undertaken in 2013 sought to determine trends in disease incidence after some significant changes occurred in the cultivar mix. Crop resistance had shifted significantly with a change in cultivar resistance and there was a consequent increase in disease severity. Financial losses from reduced yield were estimated at $5.5 million in 2013; this compares to just under $1.0 million in 2004. This paper reports on a third survey in 2018 that is a five-year update to provide snapshot of the status of this disease in the Tully sugar industry. While the disease is still widespread, its severity has decreased with financial losses estimated to be $3.5 million. Key words Pachymetra root rot, surveys, Tully, spores, cultivars